Re: Sablevm shared libraries question

Brandon Heller wrote:
> Also, I could find no documentation on how shared libraries are used
> in SVM.  If someone could reply with a bit of info on that, for the
> sake of better docs, I'd really appreciate it.  My next step will be
> to try VTune, but I expect the same issue to happen.  What tools do
> you guys use to profile/tune SVM?

I have only ever gotten qprof to work, it's available from HP's website.
You'll need libunwind from there as well.  gprof does not work with 
multithreaded programs, so it is a lost cause.  Ulrich Drepper, the 
maintainer of glibc actually said, "gprof is useless in today world."

I'm not entirely positive about the static vs. shared library stuff.  I 
do know that --enable-debugging-features will give you -O0, disable 
function inlining, and use the basic switch interpreter, and 
--with-profiling=gprof should be good for you too (this disables the 
static keyword before functions and sets -pg, even if you're not using 
gprof).  Also, since you'll get lots of errors without the static 
keyword, use --disable-errors-on-warnings.

If you're interested in hardware counters and system-wide stuff, look at
Prospect and OProfile.  I have personally been using the RDTSC 
instruction to time pieces of code within a function or execution phases 
that cross function boundaries.  You can grep around in my sandbox for 
details -- svn+ssh://svn.sablevm.org/public/developers/chris.  If you do 
decide to do something fine-grained like this, I would recommend putting 
it inside #ifdef blocks somehow so as not impact on normal execution.

There was something else that I heard about, but I can't remember its
name, so let me know if none of these suggestions work for you.

Cheers,
Chris

[please CC me, I'm not on the sablevm-devel list atm, although strangely 
I got this message.]